Should you use a buss compressor on your mix?

That’s a question I get asked a lot, and as a mastering engineer, I’m conflicted about what advice to give. The follow-up, “should it be single or multi-band ?” is easier to answer, though.

First of all:

Why would you use a buss compressor over your whole mix anyway ?

This post started out as a comment on The Recording Revolution about buss compression, and Graham’s video from that post (above) gives a good explanation.

He’s pretty clear that you should compress your whole mix, and the truth is that almost all “name” engineers in the pop, rock and indie genres, will slap an SSL or similar buss compressor over the mix as one of the first things they do when setting up a mix.

Simple, right ?

Well… maybe. A great buss compressor used on a great mix will often “glue it together” nicely, as Graham says. It’s a tried and tested technique that has been used on a huge number of hit records.

BUT:

As a mastering engineer, I’ve heard more over compressed mixes than I’ve had hot dinners.

OK, not quite that many, but you get my point. For whatever reason, this is an aspect of the mix that people get badly wrong. A LOT.

And what that means, is mixes that are

Dull, and lifeless

Pumping – and not in a good way

Heavily compressed but still not “glued” in the way you want them to be, or even

“Smashed” and distorted

And unfortunately, it’s almost impossible to remove the effects of too much compression. Sometimes you can help things out a little bit, but often by this stage it’s too late.

When this happens, I gently point out the problems to my clients, and ask if they have a less compressed version, and often the answer is “no” – or more likely, just that there isn’t any time left to sort one out.

So as a mastering engineer, I’m often tempted to say to people – DON’T use a buss compressor.

BUT:

Then they lose all the benefits ! Buss compression done right is a key component of a great sound in many modern genres. And if their goal is great sound like the classic tracks in their collection, it’s a skill they probably need to learn – sooner, rather than later.

So hopefully you can see I have dilemma. (That doesn’t mean I’m going to duck the question, though – keep reading !)

Buss Compressor “Do’s” and “Don’ts”

If you want to use a buss compressor:

DO: Add it early in the mix process

Slapping something over the mix as an after-thought will unbalance all the decisions you’ve made so far, and likely end up in an over-compressed mess.

DON’T: Push it too hard !

I was really relieved at the end of his video that Graham eased back on his settings and stressed the importance of listening out for over-compression. To find out how to avoid over-compressing your mix, click here.

DO: Get the best buss compressor you can lay your hands on

It’s possible to get a good sound from the “stock” compressors included with most DAWs, especially if you stick to gentle compression. However the hardware “classics” like Neve, Fairchild and SSL all have pretty decent plugin emulations these days by UAD, Waves and others – and they could well add an extra certain “something” that the others may not. (To see an example of a more affordable plug-in candidate, click here.)

DON’T: Assume you have to compress everything

Alan Parsons famously put the whole mix of “Dark Side Of The Moon” through a buss compressor – but not the drums. Rules are made to be broken, especially rules of thumb !

DO: Listen carefully

If a mix isn’t happening for some reason, try knocking the buss compressor out, and see if it sounds better. If it sounds right, it is right – but don’t overdo it. (Metallica, I’m looking at you !)

So – should you use a buss compressor on your mix ?

Yes.

And… No.

Depending.

Seriously though – Yes, if you’re mixing pop, rock, or anything vaguely “alt”, you should probably be using a decent buss compressor. Just remember – take time to learn what it does, and – less is more. Always listen carefully. Keep an eye on the TT loudness meter, and if you’re constantly going into the orange or the red (for a mix) make sure you’re happy with the results.

And finally, most importantly – if you’re in any doubt about the end results, do a separate mixdown for your friendly neighbourhood mastering engineer with the compressor in bypass (and remember to reduce the gain if the output starts clipping !)

Take both to the session – that way he or she will know what you were aiming for, and give you an honest opinion about the end result.

In fact, maybe you should do that even if you’re not in any doubt – just to be on the safe side : )
– Oh, I almost forgot !

Should I use a multi-band compressor on my mix ?

No.

This one really is simple. Here’s why:

The light “pumping” effect of a classic buss compressor is a key part of the sound.

Multi-band compressors don’t do this unless you push them WAY too hard (which is a Bad Thing – see above.)

Mixing into a multi-band can actually be easier – because it’s doing a lot of the hard work for you.

By their very nature, multi-bands even out mixes, pull things together and level out dynamics – in other words, it’s doing lots of the mixing work for you ! And that is not a good thing – there’s no way a plugin can be a substitute for your ears and musical taste. When mixing, anything a multi-band compressor can achieve is better done by hand.

Mastering is a whole other story of course – keep an eye out here for more on that subject soon…
PS. Do you use buss compression ? Why ?

PPS. I’ve decided to enable Facebook comments as an experiment – feel free to try them out and let me know what you think !

Comments

I’ve been following and enjoying Graham’s video series of mixing techniques during May.

I commented on the bus compression thread over there and would like to share a thought here as well.

I think the issue is blurred because people are approaching this topic from very different places. I use bus compression including a multi-band compressor and limiter on my master bus. I do this to achieve what I consider to be a finished and “mastered” sound.

Now, if I were to send the mix off to a mastering engineer to do the mastering on it, I would remove the multi-band compressor and limiter and send the unprocessed mix to the mastering engineer.

I would probably also send along a copy of the processed version as well to be used as a reference.

So, my point is that not everyone intends to send their mixes out to a mastering engineer and in this scenario bus compression certainly seems like a good idea.

It’s true that the loudness issue plays a role in this, but I don’t really agree with your conclusion.

Its perfectly possible to mix using buss compression and still maintain a good healthy dynamic range in the mix. Even though I suggest taking an uncompressed version along to the mastering session, quite often when people do this, I choose to use the compressed version.

Because, as I say in the post, buss compression can have an important ‘gluing’ effect on the mix, even when lightly used. If you’ve used this technique successfully, there’s no point in asking a mastering engineer to try and recreate that effect…

Nice, balanced post on the subject. I tend to use buss compression, mostly for the character it adds, and the way instruments seem to interact differently and better, when compressed slightly all together on the mix buss. I often find that a high-pass filter on the sideschain helps to avoid the kick ducking the mix as a whole.
A point against buss comp, which your post doesn’t mention, is that things get complicated if you plan on delivering your mix in stems to the mastering engineer. Stems can be a good option, especially for mixes made in smaller, sub-optimal rooms, but then you should either stick to compressing the individual stems, or bring your buss compressor to the mastering studio (and check the levels of the converters while your at it!).

This is well written and nicely balanced. I think if someone uses a bus compressor across a mix with care it can become one with the mix and I do not feel I have any place to suggest they should not use their prized compressors. As mentioned it is when they are over used and have “dug in too deep” and start to stifle transients, remove the space and congest that it can them be a problem. A little goes a long way and often it’s the tone of the unit itself that adds something extra not necessarily the gain reduction character, a dB or 2 off the top can work wonders when your time constants are well set up.

Ian, thanks for your post! It’s so nice to hear from a mastering engineer. One of the things I’ve done so far is to get in an almost exclusive relationship with my mastering engineer… We talk for hours and discuss what we like and don’t from each other work. And we have come to happy mediums and happy workarounds. Sometimes my mixes are good and he goes with them. Sometimes he calls me and says – send me stems, I don’t like your compression here or there… And sometimes, like you mention, I send him stuff with / without compression.

For one – I have used the multiband on my submaster bus, and I’ve also used regular compression. I guess, it’s all about how it sounds in the end and if I’m okay with what I’m hearing everywhere on my tracks!

Thanks for commenting – and, I couldn’t agree more. Having a good working relationship with a mastering engineer is essential – one of the problems with “online” services is people just sending things off without any kind of conversation and expecting the engineer to “just know” what’s needed.

Sometimes that can work, but 9 times out of 10, communication is better !

I’ve been using the waves ssl bus compressor on my masterchain. Really works like a charm. Still having problems with finding the right settings sometimes, but i guess there is no “right” setting at all.

I am in the dance music myself and as i do understand, mastering must be left to the pro’s, i trying to learn as much as i can because lets be honest, a good mastering engineer cost a lot (which its worth it) buy hey, no big bank account over here.

Just got into your videos recently, and the information you are putting out is high quality stuff, really enjoying what I’m reading, very clearly explained stuff.

I liked your suggestion from another post about automating reverb levels (id like to hear the example of that sax solo you mentioned!) I was wondering what you thought about automating the compression on the master, have you ever done this, and if so, how and why?

As far as automating mastering compression, the answer is no – I usually choose one setting per song and stick to it. What I DO do is automate the level of what’s going into it, sometimes – so, if the verse sounds great but the chorus goes over the top, easing the input the compressor back a dB or two will sometimes get you back in the right area, and not actually sound any quieter.

I’ve tried buss compression, and for some styles of music, it really works well. But a lot of that is dependent upon the quality of the compressor that you’re using. IMO, most stock plug-ins that come with a professional DAW are good for taming dynamics on a channel, but not necessarily the best when you’re trying to tame an entire mix on the master output. Unless you use it very lightly.

There are some pretty good buss compressor plug-ins that you can purchase that will help “glue” a mix together. However, I still feel that no plug-in keeps the stereo image and “glue” together as well as a h/w compressor. Also, if you’re going to end up lightly using a compressor on the buss mix, then you might as well just mix it with automated mixing in the first place!

Ultimately, I’ve found that using a limiter, rather than hard buss compression does a better, and more musical job dynamically than a compressor. But, that’s just my professional opinion…

If you mean a digital brick wall limiter, I strongly disagree. These are very transparent for small amounts of gain reduction, so don’t provide much “glue”. If you push them harder they become more effective, but I find the high ratios much too aggressive. (I use ratios of more like 2:1 with buss compression).

If you mean classic analogue compressor/limiters then I’m more likely to agree with you…

Hi Ian, I don’t have much to add but to say thank you for your always insightful articles in what tends to be an intimidating and often times too vast world for new people starting out. It’s most enjoyable when those who are actual experts in the field help us. As one of my favorite experts to read you always insert a great combination of non-vulgar, enjoyable humor with great technical advice that is easy(ier) to follow while never (appearing anyway) dumb-ing it down. Win win for me, for sure! Thank you! Really got a lot of out of this article. Now if I could apply just a 1/10 of what I read! 🙂 ~ Kim

When using parallel compression on kicks and snares,is there any need to add a limiter on the individual channels also? I see people do it and i wonder why. Whats the point if a limiter is going to be used on the master buss? Or are they just trying to tame the peaks that escape the compressor? But then again,whats the point if the peaks are going to be dealt with in the end anyway? Am i missing something?

I don’t mix music for a living, though I have mixed a few small concerts and some DJ work. I primarily listen to music. I have only one comment – STOP USING COMPRESSORS AND LIMITERS!!!!!!!!!

I can’t listen to anything recorded after 1995 (really 1992, and even some stuff from ’89). A whole generation of music has been destroyed by heavy handed compression. It’s loud, shouty and irritating!!! I feel like the singer is in my face screaming at me, and I can’t turn the volume down low enough to make it soothing. Neil Diamond’s “The Bang Years,” what a travesty!!! Music should sooth the savage beast, not irritate him. I wonder if anyone at the RIAA has looked at compressor/limiter usage vs. music sales. I bet the drop-off in music purchases would track the rise in the heavy-handed use of compressors and limiters, not the rise of Napster. Luckily there is a huge library of music from the 60’s, 70’s and 80’s on ebay and the like. When I see the words, “Remastered,” I run like hell because I know it doesn’t just mean a little EQ on a master tape, it means SHOUT, SHOUT, SHOUT in my ear. Three Blind Mice has some of the best recordings I’ve ever heard, but buy a recent CD transfer, and hear how they’ve destroyed the most natural sounding recordings ever recorded! There used to be a palpable sense that the musician was playing in an acoustic space right in front of you. Now it sounds like your ear is against the instrument and you can’t hear the acoustic space. I’ve looked at music using Cooledit 2000, and what used to be rounded, sinusoidal waves now look like triangular, sawtooth waves. This might make the music sound “snappy,” but after a few moments, it just becomes irritating. Quit using whatever device is doing that!!! Just keep compressing the music, compress it down to 1dB and record it at the 0dB level on the CD. Now we can listen to musical (and I use the term loosely) white noise – all frequencies at the same time.

Okay, after all that ranting, yes, I know limiters and compressors can be an absolute necessity. Telarc can’t get that cannon shot or lightning strike on a CD at their full dynamic range, but they did a good job of preserving the dynamics of the sound. Ditto for trumpets and drums, but a little advice – remember the old trick of trying to match a subwoofer’s level with the mains. You turn up the sub until you hear it, but then back it off a bit because when you turn it up to the point of hearing it, you’ve turned it too loud for the main system and it will be too much, too boomy. Well, do the same with compressors/limiters – turn them up just enough to hear a difference, but turn it back some so it won’t stand out. Most mixers apparently turn it up, hear a difference, then turn it up again because if a little is good, then a lot is better – NOT!!!!!!!!!!!

A music listener’s 2 cents.
Now I’ll go listen to those few thousand CD’s I have of which the bulk was NOT pressed after the 1990’s.

Mixing engineers should NOT use compression on the master bus. He should leave that up to the mastering engineer, who’s job it is to fix possible errors by the mixing engineer and add the finishing touch(de-essing, limiting the dynamics, fixing stereo image for mono compatibility)and maximizing the loudness.

As a mixing engineer your only job is to make sure the balance between instruments is good, that there are no clashing frequencies and you deliver a clean mix to the mastering engineer. The gluing of the whole track is the mastering engineer’s job.

Hallo Ian, i can just tell u that i am totalls with you. I think a lot of perple out there doft quite get what compressor is there for and we have quite some issues tovdeql with sometimes.
When we have the Chance tobmix and afterwerds Master a Song we always Use a Bus compressor. But, we aint Mix into it until the whole Mix itself Sounds great, we just Use it like a Very smooth pre limiter to taim out Peaks. I think that a great Mix can live without Masterbus compression.